Process for dyeevg wool with com-



PROCESS FOR DYEING WOOL WITH COM- PLEX HEAVY METAL MONOAZO AND AZO MLETHINE DYESTUFFS Adolf Binder and Hans-Rudolf Hirsbrunner, Basel, Switzerland, assignors to J. R. Geigy A.-G., Basel, Switzerland No Drawing. Application November 15, 1954, Serial No. 469,033 Claims priority, application Switzerland November 24, 1953 9 Claims. (Cl. 843) The subject of copending application, Serial No. 410,- 433, filed February 15, 1954, is a quick process for the dyeing of wool, if desired of wool mixed with other textile fibres in particular with synthetic polypeptide fibres which are similar to wool. The dyestuffs used in this process are complex heavy metal compounds of monoazo and azomethine dyestuffs which contain 2 dyestuff molecules to 1 heavy metal atom and, with the exception of any carboxyl groups present taking part in the complex formation, which contain no acid water solubilising groups. This process consists in putting the goods to be dyed direct into a hot dyebath prepared with the above named heavy metal compounds of dyestuifs, the pH value of the bath being at least 7.5, and completing the dyeing at the boil and decreasing. pH value while strongly circulating the liquor or moving the goods well. Dependent on the depth of the shade and the type of dyestuff used and the agent used to lower the pH value, in this manner very thoroughly penetrated, even, fully developed dyeings which have good fastness properties are obtained in the very short time of from 10 to 30 minutes.

The ammonium salts of inorganic or organic acids or esters of low molecular alcohols, in particular those of aliphatic hydroxycarboxylic acids, for example are used as agents to lower the pH value. According to the alkalinity of the wool and the water used, the type and amount of the agent used to lower the pH value, and according to the length of the dyeing time, it is possible in this manner to reduce the pH value of the dyebath during dyeing to about 6.5.

The best results are obtained with this process in a weakly alkaline pH range by which the pH value of the liquor can be kept under that limit of alkalinity which would cause considerable damage to the wool.

Although the pH conditions to be observed in this process can be regarded as really not injurious to the material, it has been noticed when dyeing wool, even in only weakly alkaline baths, that the goods have a rather bad feel and cannot be spun so easily. In particular for loose wool, slubbing and in some cases also for knitting wool, there is a need, therefore, for a quick acid dyeing process.

It is known however, that in the acid pH range, particularly however in hot acid baths, the affinity of these heavy metal containing dyestuffs to natural and synthetic polypeptide fibres is so great that, because of too quick exhaustion of the baths, only uneven dyeings are obtained which technically are unusable. Up to now, it has been attempted to overcome this difiiculty by either entering the goods into the liquor containing the dyestuif at a low temperature or by adding the dissolved dyestuff to the dyebath at low temperatures of 40 to 60. The dyeing then proceeded at a relatively long drawn out warmmg and dyeing time under exact temperature control, whilst in particular the critical temperature of from 70 to 80 C. was very slowly passed, if necessary by completely halting the increase in temperature. For this purpose an acid buffer mixture of alkali metal acetate and acetic nite States Patent U F acid has proved to be much superior to the sodium sulphate-sulphuric acid mixture usual in Wool dyeing.

The subject of the present invention is thus a quick dyeing process for W001, if desired mixed with other textile fibres similar thereto, with complex heavy metal compounds, in particular complex chrominum and cobalt compounds of monoazo and azomethine dyestuffs which contain 2 dyestulf molecules to 1 heavy metal atom and with the exception of any carboxyl groups present taking part in the complex formation-which contain no acid water solubilising groups but on the other hand which contain preferably alkylsulphonyl groups, sulphonic acid amide groups and sulphonic acid amide groups organically substituted at the nitrogen atom to enhance the water solubility. It consists in pre-treating the wool-- advantageously in the dyebath containing no dyestuif in a hot or heated mineral acid well-circulating liquor in such a manner that the final pH value of the liquor is constant between 4.0 and 6.0 whereupon the dyestuff is added at a temperature of over advantageously dissolved in water, and dyeing is continued in the presence of capillary active polyglycol ethers containing no nitrogen while circulating the warm liquor or moving the goods thoroughly until the bath is to all intents and purposes exhausted.

The acid treatment of the wool in the warm or while warming serves to convert it in the acid medium into a condition approaching that in which it can combine with acid. It is known that acid combination with wool begins at a pH value of the liquor of 4.5 to 4.8. The pre-treatment with mineral acid therefore must be performed so that the final pH value of the liquor is constant between 4.0 and 6.0. Because of diifusion and membrane effects in or on the wool, to adjust this constant final pH value, a treatment time which is dependent on the temperature is necessary. This time for example can be hours in the cold, about 15 minutes at medium temperatures of 50 to 60 C. and can be about 5 minutes at higher temperamust be under 4.0. The most favourable amount of acid 7 however is that which gives a constant final pH value as near as possible to that value at which the wool begins to be capable of combining with acid. This can be easilyascertained for the particular material used by a series of previous tests. The use of a polybasic, strongly dissociating mineral acid is advantageous in the process according to the present invention; sulphuric acid is preferable and if desired also phosphoric acids. It is of advantage to add the acid to the circulating liquor in the dyeing apparatus before or during the heating whereby, even with rapid heating, the time taken to reach a temperature of 8085 C. is generally completely sufficient to attain the constant final pH value of the liquor. If carbonised wool is used then the addition of acid is generally not necessary for the adjustment of a constant pH final value of the liquor from 4.0 to 6.0; often it is rather the case that phatic or aliphatic-aromatic hydrocarbon radical having at least 10 carbon atoms, for example addition products of fatty alcohols such as for example dodecyl alcohol,

hexadecyl alcohol, octadecyl alcohol, oleyl alcohol or Patented Dec. 24, 1957 from mixtures of such and similar fatty alcohols, or of alkylated phenols such as 4-isooctyl phenol, 2.4-di-tert. butyl or -di-tert, amyl phenol, 4-dodecyl phenol, 3- or 4- nonyl phenol and, for example 10 to 30 mols of ethylene oxide. It is of advantage to add them to the dyestuif solution before dyeing is begun. They can however also be added to the liquor before the dyestuif solution. Amounts of 0.1 to 2 grammes per litre dye liquor for example are used according to the depth of the shade to be attained.

Dyeing can be finished in the process according to the present invention at 80 to 100. It is preferable however to raise the temperature to the boil in an open vessel or to exceed 100 C. when Working under pressure in a closed vessel.

It is surprising that, while overcoming justified prejudices, in the process according to the present invention it is possible to dye perfectly evenly on to Wool heavy metal containing dyestuffs which contain no sulphonic acid groups and no carboxyl groups not taking part in the complex formation from a mineral acid bath by a quick method. It is also particularly characteristic of the inventive nature of the new method that even when working under the same conditions-the use of mineral acids gives by far better results than the use of the organic acids chiefly used up to the present in similar hot acid baths, such as e. g. acetic acid and formic acid.

The following examples illustrate the invention without limiting it in any way. Parts are given as parts by weight and the temperatures are in degrees centigrade.

Example 1 Dyeing is performed on the principle of stationary material and circulating liquor. A packing apparatus serves as a liquor container. The apparatus is loaded in such a way that slubbing is wound on perforated tubes screwed into the container which serve as holders for the goods. The liquor is circulated from a pump through the perforated tubes from the inside to the outside. Liquor ratio 1:50.

Method.--l parts of wool slubbing Wound on perforated tubes are dyed in the packing apparatus as follows: 5,000 parts of soft water are poured in, the circulation pump is set in motion, 1 part of sulphuric acid (98%) is added and the bath is heated quickly to 90 with indirect steam. At 90, 1.5 parts of the grey complex chromium compound of the monoazo dyestuff 2-aminophenol-4-ethyl sulphone acetylamino-naphthol- 1.7) and 2.5 parts (corresponding to 0.5 g. per litre dyebath) of an addition product of 2.4-di-tert. amyl phenol and 12 mols of ethylene oxide, both well dissolved in hot water are added. The bath is then quickly brought to the boil and after boiling for 30 minutes the dyeing is completed after the bath has been almost completely exhausted and the pH value has risen from 5.1 to 5.5.

The tops are dyed evenly through and through in a grey shade.

Example 2 100 parts of loose wool are dyed in the packing apparatus above described: The procedure is the same as that described in example 1 with the difference that 1.5 parts of sulphuric acid (98%) are used and then the bath is heated direct to 100. 1 part of the grey complex chromium compound of the monoazo dyestuff Z-aminophenol sulphonic acid methylamideacetylaminonaphthol-(1.7) and 0.2 part of the wine red cobalt compound of the azo dyestuif from Z-aminophenol-4-sulphomethylamidefl-naphthol together with 5 parts (corresponding to 1 g. per litre dyebath) of a mixed addition product of cetyl+oleyl alcohol and mols of ethylene oxide well dissolved in hot Water are added to the boiling bath. The bath is almost completely exhausted within 30 minutes during which time the pH value has risen from 4.2 to 4.5.

Loose wool very evenly dyed in a silver grey shade is obtained.

Example 3 100 parts of wool slubbing wound on to tops are dyed in the packing apparatus according to Example 1 as follows:

The same procedure is followed as in Example 2 and the same mixture of dyestuffs with the same concentration is used; instead of sulphuric acid however, 1 part of phosphoric acid (84%) is added. During dyeing the pH value of the dyebath rises from 5.3 to 5.7.

Tops dyed very evenly through and through in a silver grey shade are obtained.

Example 4 5,000 parts of soft water are put into the packing apparatus described in Example 1. 100 parts of carbonised wool wound on to tops are entered, the circulation pump is set in motion and the bath is heated by direct steam. If necessary, at a temperature of from 60-80 the pH value of the bath is adjusted to 4 to 5 with the aid of disodium phosphate. After 10 minutes at the solution of 0.5 part of the yellow complex cobalt compound of the monoazo dyestuff Z-aminophenol-4-methyl sulphoneacetoacetic acid-o-chloranilide together with 5 parts (corresponding to 1 g. per litre dyebath) of an addition product of dodecyl alcohol and 25 mols of ethylene oxide are added. The bath is quickly brought to the boil and dyeing is performed for a further 20 minutes.

Tops which have been dyed a yellow colour very evenly through and through are obtained.

Example 5 Dyeing is performed according to the principle of stationary material and circulating liquor. A so-called hank dyeing machine is used as liquor container. The hanks are suspended from dyesticks which are fitted into the hank frame from which they can be removed. The hank frame holding the dyesticks is inserted into the liquor container and the liquor is pumped through the apparatus from a circulation pump. Liquor ratio 1:33.

MetIz0d.-A bath is prepared in the hank dyeing machine consisting of 3,300 parts of soft water and 1.5 parts of sulphuric acid (98%). t is heated to 90 and 100 parts of woollen knitting yarn in the form of hanks are entered. The bath is run for 15 minutes at 90, whereupon the goods are taken out of the bath. 1.5 parts of the rust brown complex chromium compound of the monoazo dyestuff 4-nitro-2-aminophenol 3.4-dimethyll-phenol together with 3.3 parts (corresponding to 1.0 g. per litre dyebath) of an addition product of nonylphenol and 10 mols of ethylene oxide are added and the goods are again entered. The dyeing is performed and completed in the usual way as described in the above examples.

Knitting yarn which has been very evenly dyed a rust brown shade is obtained.

The following table contains further dyestuffs which can be dyed in an analogous manner by the method described in the above examples.

What we claim is:

l. A method for the dyeing of wool with complex heavy metal compounds of dyestuffs selected from the group consisting of monoazo and azo methine dyestulfs of the type containing two dyestuff molecules to one heavy metal atom which contain no acid water solubilising groups, which comprises pro-treating wool in circulating hot water with a strongly dissociating polybasic mineral acid, adjusting the acid reaction of said hot water to a final pH value of from 4 to 6 at the end of the pretreatment, then adding an aqueous solution of the dye stuff at a temperature of at least 80 C. and dyeing at a temperature of from 85 to 100 C. in the presence of an addition product of from 10 to 30 mols of ethylene oxide to a hydroxy compound of a lipophilic hydrocarbon until the dye-liquor is substantially free from dyestuif.

A method for the dyeing of wool with complex heavy metal compounds of dyestuffs selected from the group consisting of monoazo and azo methine dyestuffs of the type containing two dyestulr molecules to one heavy metal atom which contain no acid water solubilising groups, which comprises pro-treating scoured wool in circulating hot water with sulphuric acid, adjusting the acid reaction of said hot water to a final pH value of from 4 to 6 at the end of the pretreatment, then adding an aqueous solution of the dyestuff at a temperature of at least 80 C. and dyeing at a temperature of from 85 to 100 C. in the presence of an addition product of from 10 to 30 mols of ethylene oxide to a hydroxy compound of a lipophilic hydrocarbon until the dye liquor is substantially free from dyestuff.

3. A method for the dyeing of wool with complex heavy metal compounds of dyestufis selected from the group consisting of monoazo and azo methine dyestuffs of the type containing two dyestutf molecules to one heavy metal atom which contain no acid water solubilising groups, which comprises pro-treating scoured wool in circulating hot water with phosphoric acid, adjusting the acid reaction of said hot water to a final pH value of from 4 to 6 at the end of the pro-treatment, then adding an aqueous solution of the dyestuli at a temperature of at least 80 C. and dyeing at a temperature of from 85 to 100 C. in the presence of an addition product of from 10 to 30 mols of ethylene oxide to a hydroxy compound of a lipophilic hydrocarbon until the dye liquor is substantially free from dyestuff.

4. A method for the dyeing of wool with complex heavy metal compounds of dyestuifs selected from the group consisting of monoazo and azo methine dyestuffs of the type containing two dyestultf molecules to one heavy metal atom which contain no acid water solubilising groups, which comprises pro-treating sulphuric acid-containing carbonised wool in circulating hot water, adjusting the sulphuric acid reaction of said hot water with a butler salt to a final pH value of from 4 to 6 at the end of the pre-treatment, then adding an aqueous solution of the dyestufl? at a temperature of at least 80 C. and dyeing at a temperature of from 85 to 100 C. in the presence of an addition product of from 10 to 30 mols of ethylene oxide to a hydroxy compound of a lipophilic hydrocarbon until the dye liquor is substantially free from dyestufi.

5. A method for the dyeing of wool with complex heavy metal compounds of dyestuffs selected from the group consisting of monoazo and azo methine dyestuffs of the type containing two dyestufi molecules to one heavy metal atom which contain no acid water solubilising groups, which comprises pro-treating scoured wool in circulating hot water with sulphuric acid, adjusting the acid reaction of said hot water to a final pH value of from 4 to 6 at the end of the pro-treatment, then adding an aqueous solution of the dyestuff at a temperature of at least C. and dyeing at a temperature of from 35 to 100 C. in the presence of an addition product of 1.0 mols of ethylene oxide to hexadecyl alcohol until the dye liquor is substantially free from dyestuff.

6. A method for the dyeing of wool with complex heavy metal compounds of dyestuiis selected from the group consisting of monoazo and azo methine dyestuffs of the type containing two dyestuif molecules to one heavy metal atom which contain no acid water solubilising groups, which comprises pro-treating scoured wool in circulating hot water with sulphuric acid, adjusting the acid reaction of said hot water to a final pH value of from 4 to 6 at the end of the pretreament, then adding an aqueous solution of the dyestuft at a temperature of at least 80 C. and dyeing at a temperature of from to C. in the presence of an addition product of 12 mols of ethylene oxide to 2.4-di-tert. amyl phenol until the dye liquor is substantially free from dyestutf.

7. A method for the dyeing of wool with complex heavy metal compounds of dyestuffs selected from the group consisting of monoazo and azo methine dyestufis of the type containing two dyestulf molecules to one heavy metal atom which contain no acid water solubilising groups, which comprises pro-treating scoured wool in circulating hot water with phosphoric acid, adjusting the acid reaction of said hot water to a final pH value of from 4 to 6 at the end of the pre-treatrnent, then adding an aqueous solution of the dyestuff at a temperature of at least 80 C. and dyeing at a temperature of from 85 to 100 C. in the presence of an addition product of 10 mols of ethylene oxide to hexadecyl alcohol until the dye liquor is substantially free from dyestufi.

8. A method for the dyeing of Wool with complex heavy metal compounds of dyestuffs selected from the group consisting of monoazo and azo methine dyestufls of the type containing two dyestulf molecules to one heavy metal atom which contain no acid water solubilising groups, which comprises pro-treating sulphuric acidcontaining carbonised wool in circulating hot water, adjusting the sulphuric acid reaction of said hot water with disodium orthophosphate to a final pH value of from 4 to 6 at the end of the pro-treatment, then adding an aqueous solution of the dyestutf at a temperature of at least 80 C. and dyeing at a temperature of from 85 to 100 C. in the presence of an addition. product of 25 mols of ethylene oxide to dodecyl alcohol until the dye liquor is substantially free from dyestufi.

9. A method for the dyeing of Wool with complex heavy metal compounds of dyestufis selected from the group consisting of monoazo and azo methine dyestuffs of the type containing two dyestufl molecules to one heavy metal atom which contain no acid water solubilising groups, which comprises pro-treating scoured wool in circulating hot water with sulphuric acid, adjusting the acid reaction of said hot water to a final pH value of from 4 to 6 at the end of the pro-treatment, then adding an aqueous solution of the dyestuif at a temperature of at least 80 C. and dyeing at a temperature of from 85 to 100 C. in the presence of an addition product of 10 mols of ethylene oxide to nonyl phenol until the dye liquor is substantially free from dyestutf.

No references cited. 

1. A METHOD FOR THE DYEING OF WOOLWITH COMPLEX HEAVY METAL COMPOUNDS OF DYESTUFFS SELECTED FROM THE GROUP CONSISTING OF MONOAZO AND AZO METHINE DYESTUFFS OF THE TYPE CONTAINING TWO DYESTUFF MOLECULES TO ONE HEAVY METAL ATOM WHICH CONTAIN NO ACID WATER SOLUBILISING GROUPS, WHICH COMPRISES PRE-TREATING WOOL IN CIRCULATING HOT WATER WITH A STRONGLY DISSOCIATING POLYBASIC MINERAL ACID, ADJUSTING THE ACID REACTION OF SAID HOT WATER TO A FINAL PH VALUE OF FROM 4 TO 6 AT THE END OF THE PRETREATMENT, THEN ADDING AN AQUEOUS SOLUTION OF THE DYESTUFF AT A TEMPERATURE OF AT LEAST 80*C. AND DYEING AT A TEMPERATURE OF FROM 85* TO 100*C. IN THE PRESENCE OF AN ADDITION PRODUCT OF FROM 10 TO 30 MOLS OF ETHYLENE OXIDE TO A HYDROXY COMPOUND OF A LIPOPHILIC HYDROCARBON UNTIL THE DYE-LIQUOR IS SUBSTANTIALLY FREE FROM DYESTUFF. 